Move tests to separate folder

tests/solvers/__init__.py

@@ -0,0 +1,70 @@
+#  MIPLearn: Extensible Framework for Learning-Enhanced Mixed-Integer Optimization
+#  Copyright (C) 2020, UChicago Argonne, LLC. All rights reserved.
+#  Released under the modified BSD license. See COPYING.md for more details.
+
+from inspect import isclass
+from typing import List, Callable, Any
+
+from pyomo import environ as pe
+
+from miplearn.instance import Instance
+from miplearn.problems.knapsack import KnapsackInstance, GurobiKnapsackInstance
+from miplearn.solvers.gurobi import GurobiSolver
+from miplearn.solvers.internal import InternalSolver
+from miplearn.solvers.pyomo.base import BasePyomoSolver
+from miplearn.solvers.pyomo.gurobi import GurobiPyomoSolver
+from miplearn.solvers.pyomo.xpress import XpressPyomoSolver
+
+
+class InfeasiblePyomoInstance(Instance):
+    def to_model(self) -> pe.ConcreteModel:
+        model = pe.ConcreteModel()
+        model.x = pe.Var([0], domain=pe.Binary)
+        model.OBJ = pe.Objective(expr=model.x[0], sense=pe.maximize)
+        model.eq = pe.Constraint(expr=model.x[0] >= 2)
+        return model
+
+
+class InfeasibleGurobiInstance(Instance):
+    def to_model(self) -> Any:
+        import gurobipy as gp
+        from gurobipy import GRB
+
+        model = gp.Model()
+        x = model.addVars(1, vtype=GRB.BINARY, name="x")
+        model.addConstr(x[0] >= 2)
+        model.setObjective(x[0])
+        return model
+
+
+def _is_subclass_or_instance(obj, parent_class):
+    return isinstance(obj, parent_class) or (
+        isclass(obj) and issubclass(obj, parent_class)
+    )
+
+
+def _get_knapsack_instance(solver):
+    if _is_subclass_or_instance(solver, BasePyomoSolver):
+        return KnapsackInstance(
+            weights=[23.0, 26.0, 20.0, 18.0],
+            prices=[505.0, 352.0, 458.0, 220.0],
+            capacity=67.0,
+        )
+    if _is_subclass_or_instance(solver, GurobiSolver):
+        return GurobiKnapsackInstance(
+            weights=[23.0, 26.0, 20.0, 18.0],
+            prices=[505.0, 352.0, 458.0, 220.0],
+            capacity=67.0,
+        )
+    assert False
+
+
+def _get_infeasible_instance(solver):
+    if _is_subclass_or_instance(solver, BasePyomoSolver):
+        return InfeasiblePyomoInstance()
+    if _is_subclass_or_instance(solver, GurobiSolver):
+        return InfeasibleGurobiInstance()
+
+
+def _get_internal_solvers() -> List[Callable[[], InternalSolver]]:
+    return [GurobiPyomoSolver, GurobiSolver, XpressPyomoSolver]